Image display apparatuses having organic EL (Electroluminescent) devices utilizing electroluminescence are conventionally known.
In an organic EL device, for example, a transparent electrode and a metal electrode are placed opposite to each other, with organic layers, including a light-emitting layer, being sandwiched between them. In an organic EL device thus structured, when a voltage or current is applied across the transparent electrode and the metal electrode, current flows in the light-emitting layer and the light-emitting layer emits light, and the light emitted from the light-emitting layer passes through the transparent electrode to the outside. It is known that, for common organic EL devices, the current density of the light-emitting layer and the luminance are nearly proportional to each other, and a conventional example thereof is disclosed in a patent document (Japanese Patent Application Laid-Open No. 2006-309258), for example.
However, the deterioration of the organic EL devices is promoted as the current density of the organic EL devices is higher, leading to shorter life of the organic EL devices, and further to shorter life of the image display apparatus.